Embedded within the walls of a 19th-century mansion in an ancient harbour town on the east African island of Zanzibar are bricks bearing an unlikely stamp: “Made in Glasgow.” The bricks – once ballast in an empty ship returning from a trading voyage – reveal the long-standing global connections of the world’s great Islamic cities, many of which have fallen into disrepair.

Rebuilding the vibrancy of some of these cities is the mission of an initiative called the “Historic Cities Programme”. But while the programme falls under the auspices of the Aga Khan Trust for Culture, the cultural agency of the Aga Khan Development Network, its work extends far beyond architectural restoration.

“If you are just dealing with individual monuments, you may not be affecting the lives of the people living around them,” says Luis Monreal, director-general of the trust. “And in Islamic cities, the highest monument concentration is always in the poorest areas.”

The trust – which believes restoring historic monuments provides a catalyst for social and economic development – is not alone in putting architectural heritage at the heart of urban regeneration.

“Each city has its own personality, its strengths and weaknesses, failures and successes,” says Anna Tibaijuka, executive director of UN-Habitat, the United Nations agency for human settlements. “The city’s ‘soul’ is exhibited through its cultural heritage, its social fabric, its intellectual and creative assets, its vibrancy and its distinct identity.”

Conservation of ancient districts preserves this individualism in the face of modernisation, argues Tibaijuka. “The emphasis on new things, clean lines and modern design is intense,” she says. “The problem with this one-size-fits-all approach to urban design is that many cities are starting to look alike, which makes them less interesting.”

However, there is another reason the Historic Cities Programme launches every project with the restoration of a monument. “One of the great obstacles to urban regeneration is the attitude of the inhabitants,” says Monreal. “Normally they are very poor, nothing good has happened in their lives and they don’t believe any promises.”

The idea is to start with something that quickly demonstrates commitment to change and generates immediate local pride. “It’s not enough to provide grants, social work and so on,” he says. “You need to do something that is visible.”

Others in the field of restoration acknowledge the truth in this. “Historic districts provide a connection with the past, which brings richness and depth to a city,” says Jeff Morgan, founder of the Global Heritage Fund, a US-based non-profit organisation that works to save endangered cultural heritage sites in developing countries.

Morgan argues heritage conservation also sparks the creation of small businesses and jobs, often through tourism, and encourages human-scale development, with pedestrian areas and districts of lower density.

Like the Aga Khan trust, the Global Heritage Fund focuses narrowly before engaging in broader restoration work. “In general, we start with a single district or class of society – very poor – where our intervention can set a model for the rest of the historic city,” Morgan explains. “By training the teams and providing vision and a plan, we can kick off a longer-term major transformation.”

In Zanzibar, the trust chose the Old Dispensary for this purpose. Originally commissioned by Tharia Topan, a prominent Indian trader, the building was well known to locals. However, for many years, it lay in ruins, beams rotting, roofs leaking, balconies tipping at alarming angles and plaster walls crumbling to reveal the bricks beneath, with their Glaswegian stamps.

In 1996, the building was opened as a cultural centre and, since then, the project has expanded into Stone Town – Zanzibar’s ancient city, a maze of narrow alleys and ornate Arab houses. Along the seafront, the trust has restored Forodhani Park, a once-derelict garden built by the British in the 1930s. During the day, it is a place for people to relax. At night, vendors set up stalls to sell snacks and meals.

“In this case, the relationship with economic development is very clear because we are optimising the opportunities generated for these food vendors and their families,” says Monreal.

A historic cities project in northern Pakistan also demonstrates this link between cultural restoration and urban regeneration. Perched on a craggy rock overlooking the town of Karimabad, the 700-year-old Baltit Fort was once empty, its rooms covered in graffiti and walls leaning precariously.

New foundations were built and high-strength polymer mesh embedded within the walls. Steel tie bars were installed to stabilise the building against tremors in what is an earthquake zone. Meanwhile, work went on in the town nestling around the base of the fort to rebuild sanitation systems and restore traditional houses.

Morgan says such cultural restoration projects help locals build confidence in their ability to participate in urban regeneration. “Once they have training and see the potential for jobs over the long term, the community take the work very seriously,” he says.

This was certainly the case in Pakistan. The Baltit Fort, another Aga Khan project, inspired the community to take action, for once locals had experienced the benefits of running water and clean drains, some decided to renovate family homes at their own expense.

More recently, the trust’s restoration of the Humayun’s Tomb gardens in 2004 has been the starting point for a broader urban renewal project. The two-year project involved replanting the gardens and rebuilding the ancient water channels representing the four rivers of the Qur’anic paradise. Engineers designed a subtle gradient – just a 1cm drop for every 30m-40m – to allow gravity to stimulate the water to flow around the channels again.

A larger-scale initiative is now under way in Nizamuddin Basti, a large green space nearby that will become an urban park, creating what Monreal calls a “magnet for socio-economic development”.

In Delhi, the urban renewal project is being run as a public-private partnership with three government agencies. And the buy-in of local leaders is essential, says the Global Heritage Fund’s Morgan, to establish historic districts, seek funding and develop a plan and creative incentives for locals to undertake preservation work. “In most cases, it’s a question of leadership and will, not monies,” he says.

When it comes to the broader regeneration elements of its work, the Historic Cities Programme can also tap into the resources of the Aga Khan Development Network, an umbrella organisation for agencies working in everything from health and education to rural development and disaster relief.

But while these agencies are often present to rebuild health and education systems, the principle of including culture remains critical to the organisation’s philosophy, even in devastated cities, where some might argue that architectural conservation is less of a priority.

However, in Afghanistan, where war has destroyed much of Kabul’s basic infrastructure, the Trust for Culture has restored the 16th-century Bagh-e Babur Gardens, the first Mughal emperor’s burial place. Unexploded mortar shells have been removed and perimeter walls rebuilt, and more than 3,000 trees have replaced those torn down for use as fuel for cooking and heating.

Monreal believes this project has been as important for the city as other forms of redevelopment. “For the people, they have not only recovered a space for leisure and family gatherings,” he says. “They have also recovered a very potent symbol of their identity.”

Tibaijuka agrees. “Cities are not just bricks and mortar,” she says. “They represent the dreams, aspirations and hopes of societies.”